Interactive Effects Of Temperature Research Articles

Interactive effects of temperature, CO2 and nitrogen source on a coastal California diatom assemblage

Interactive effects of temperature, CO2 and nitrogen source on a coastal California diatom assemblage

Pig Social Status and Chronic Cold or Crowd Stressors Differentially Impacted Immune Response

The objectives of this study were to determine the effects of 4-day of cold and crowding stressors and social status on pig immune responsiveness to these stressors. Three unfamiliar white crossbred female pigs were mixed and assigned to ambient temperatures of either 8°C (COLD) or 22°C (control; TN) and floor-space of either 0.26 m2/pig (reduced, CROWD) or 0.45 m2/pig (adequate, CONT) over six blocks (n = 72). Pigs were identified as dominant (DOM), intermediate (INT), or submissive (SUB) based on aggressive encounters that occurred during the first 24-h post-mixing. There were no interactive effects of temperature × floor-space on immune indices. There was social status × stressor for body weight, natural killer (NK) cell cytotoxicity and phagocytosis (P P P

Modeling the viscoplastic behavior and grain size in a hot worked Nb-bearing high-Mn steel

In this study, hot compression tests were performed on a Nb-containing high-Mn steel at temperatures in range of 850–1150°C and strain rates of 0.001–1s−1. The stacking fault energy of the material at different conditions, i.e. without Nb, with Nb and C in solution and with Nb and C as NbC, was calculated by JMat Pro software as 10.9, 10.15 and 10mJ/m2. The software predicted that the stacking fault energy reaches 200–250mJ/m2 as temperature rises to the deformation range. A new model with interactive effects of temperature, strain and strain rate was constructed on the basis of Johnson-Cook equation to predict the experimental flow curves satisfactorily. Optical microscopy and SEM-EBSD observations showed that strain-induced boundary migration (SIBM) is the major mechanism of dynamic recrystallization giving rise to a necklace structure at the early stages of recrystallization. It was found that very fine layers of lath martensite form within the large austenitic grains during post-deformation quenching. However, the martensite layers were less discernible in the small DRX grains. The dynamically recrystallized grain size decreased with increase in strain rate or decrease in temperature. The model developed based on Bate and Hutchinton approach showed that the recrystallized grain size has an indirect relationship with the flow stress level.

Independent and interactive effects of ambient temperature and absolute humidity on the risks of avian influenza A(H7N9) infection in China

The emergence of avian influenza A(H7N9) virus poses a pandemic threat to human beings. It was proposed that meteorological factors might be important environmental factors favoring the occurrence of H7N9 infection, but evidence is still inadequate. In this study, we aimed to investigate the independent and interactive effects of ambient temperature (TM) and absolute humidity (AH) on H7N9 infection risks in China. The individual information of all reported H7N9 cases and daily meteorological data in five provinces/municipality (Zhejiang, Jiangsu, Shanghai, Fujian, and Guangdong) in China during 2013–2016 were collected. We employed a case-crossover study design, in which the 7–10days before the onset date of each H7N9 case was defined as the hazard period, and 4weeks before the hazard period was taken as the control period. The average levels of meteorological factors were calculated during the hazard and control periods. A Cox regression model was used to estimate the independent and interactive effects of TM and vapor pressure (VP), an indicator of AH, on H7N9 infection risks. A total of 738 H7N9 cases were included in the present study. Significantly nonlinear negative associations of TM and VP with H7N9 infection risks were observed in all cases, and in cases from northern and southern regions. There were significant interactive effects between TM and VP on H7N9 infection risks, and the risks of H7N9 infection were higher in cold-dry days than other days. We further observed different risky windows of H7N9 infection in the northern (TM: 0–18°C, VP: 313mb) and southern areas (TM: 7–21°C, VP: 3–17mb). We concluded that ambient temperature and absolute humidity had significant independent and interactive effects on H7N9 infection risks in China, and the risks of H7N9 infection were higher in cold-dry days. The risky windows of H7N9 infection were different in the northern and southern areas.

Responses of phenology and biomass production of boreal fens to climate warming under different water-table level regimes.

Climate change affects peatlands directly through increased air temperatures and indirectly through changes in water-table level (WL). The interactions of these two still remain poorly known. We determined experimentally the separate and interactive effects of temperature and WL regime on factors of relevance for the inputs to the carbon cycle: plant community composition, phenology, biomass production, and shoot:root allocation in two wet boreal sedge-dominated fens, "southern" at 62°N and "northern" at 68°Ν. Warming (1.5°C higher average daily air temperature) was induced with open-top chambers and WL drawdown (WLD; 3-7cm on average) by shallow ditches. Total biomass production varied from 250 to 520g/m2 , with belowground production comprising 25%-63%. Warming was associated with minor effects on phenology and negligible effects on community composition, biomass production, and allocation. WLD clearly affected the contribution of different plant functional types (PFTs) in the community and the biomass they produced: shrubs benefited while forbs and mosses suffered. These responses did not depend on the warming treatment. Following WLD, aboveground biomass production decreased mainly due to reduced growth of mosses in the southern fen. Aboveground vascular plant biomass production remained unchanged but the contribution of different PFTs changed. The observed changes were also reflected in plant phenology, with different PFTs showing different responses. Belowground production increased following WLD in the northern fen only, but an increase in the contributions of shrubs and forbs was observed in both sites, while sedge contribution decreased. Moderate warming alone seems not able to drive significant changes in plant productivity or community composition in these wet ecosystems. However, if warming is accompanied by even modest WL drawdown, changes should be expected in the relative contribution of PFTs, which could lead to profound changes in the function of fens. Consequently, hydrological scenarios are of utmost importance when estimating their future function.

Interactive effects of temperature and moisture on composition of the soil microbial community

SummaryA wealth of knowledge exists on the response of soil processes to variation in environmental factors such as temperature and moisture, but the response from the soil microbial communities that control these processes remains poorly understood. We carried out a full factorial incubation experiment to investigate the single and interactive effects of temperature (10, 17, 24, 31 and 38°C) and moisture (20, 40, 60, 80 and 100% water holding capacity (WHC)) on composition of the soil microbial community characterized by the phospholipid fatty acids (PLFAs) method. The single and interactive effects of temperature and moisture were statistically significant (P < 0.05) for almost all the selected PLFA signatures, including fungi (F), bacteria (B), Gram‐positive bacteria (G+), Gram‐negative bacteria (G−), actinomycetes (ACT) and the bacterial stress index (BSI). Although the F/B ratio increased and the G+/G− ratio decreased with increasing temperature, they were not significantly affected by moisture and its interaction with temperature. In general, the concentrations of fungal PLFAs were smaller at higher temperatures, but not altered by changes in moisture. In contrast, the concentrations of bacterial PLFAs were larger at higher temperatures and moderate moisture contents. Although we manipulated temperature and moisture in the incubation, the treatments and the treatment‐altered soil properties (dissolved organic carbon (DOC) and inorganic nitrogen (ION)) together explained 18% of the total variation in selected PLFA signatures and the temperature effect contributed the most (12%). Significant correlations between community composition variables (F, B and F/B) and soil properties (DOC and ION) indicated substantive indirect effects of temperature and moisture on the composition of the soil microbial community by altering substrate availability. Our results suggest that soil microbial communities might shift towards a more bacteria‐dominated composition under warmer temperatures and moderate moisture conditions in subtropical forest regions.Highlights How do temperature and moisture independently and interactively affect soil microbial community composition? Concentrations of bacterial PLFAs were larger at higher temperatures and moderate moisture. Concentrations of fungal PLFAs were smaller at higher temperatures, but did not respond to moisture differences. Increased soil carbon and nitrogen availability mainly benefitted bacteria under higher temperatures and moderate moisture.

Interactive effects of temperature and habitat complexity on freshwater communities.

Warming can lead to increased growth of plants or algae at the base of the food web, which may increase the overall complexity of habitat available for other organisms. Temperature and habitat complexity have both been shown to alter the structure and functioning of communities, but they may also have interactive effects, for example, if the shade provided by additional habitat negates the positive effect of temperature on understory plant or algal growth. This study explored the interactive effects of these two major environmental factors in a manipulative field experiment, by assessing changes in ecosystem functioning (primary production and decomposition) and community structure in the presence and absence of artificial plants along a natural stream temperature gradient of 5–18°C. There was no effect of temperature or habitat complexity on benthic primary production, but epiphytic production increased with temperature in the more complex habitat. Cellulose decomposition rate increased with temperature, but was unaffected by habitat complexity. Macroinvertebrate communities were less similar to each other as temperature increased, while habitat complexity only altered community composition in the coldest streams. There was also an overall increase in macroinvertebrate abundance, body mass, and biomass in the warmest streams, driven by increasing dominance of snails and blackfly larvae. Presence of habitat complexity, however, dampened the strength of this temperature effect on the abundance of macroinvertebrates in the benthos. The interactive effects that were observed suggest that habitat complexity can modify the effects of temperature on important ecosystem functions and community structure, which may alter energy flow through the food web. Given that warming is likely to increase habitat complexity, particularly at higher latitudes, more studies should investigate these two major environmental factors in combination to improve our ability to predict the impacts of future global change.

Interactive effects of temperature, organic carbon, and pipe material on microbiota composition and Legionella pneumophila in hot water plumbing systems

BackgroundSeveral biotic and abiotic factors have been reported to influence the proliferation of microbes, including Legionella pneumophila, in hot water premise plumbing systems, but their combined effects have not been systematically evaluated. Here, we utilize simulated household water heaters to examine the effects of stepwise increases in temperature (32–53 °C), pipe material (copper vs. cross-linked polyethylene (PEX)), and influent assimilable organic carbon (0–700 μg/L) on opportunistic pathogen gene copy numbers and the microbiota composition, as determined by quantitative polymerase chain reaction and 16S rRNA gene amplicon sequencing.ResultsTemperature had an overarching influence on both the microbiota composition and L. pneumophila numbers. L. pneumophila peaked at 41 °C in the presence of PEX (1.58 × 105 gene copies/mL). At 53 °C, L. pneumophila was not detected. Several operational taxonomic units (OTUs) persisted across all conditions, accounting for 50% of the microbiota composition from 32 to 49 °C and 20% at 53 °C. Pipe material most strongly influenced microbiota composition at lower temperatures, driven by five to six OTUs enriched with each material. Copper pipes supported less L. pneumophila than PEX pipes (mean 2.5 log10 lower) at temperatures ≤ 41 °C, but showed no difference in total bacterial numbers. Differences between pipe materials diminished with elevated temperature, probably resulting from decreased release of copper ions. At temperatures ≤ 45 °C, influent assimilable organic carbon correlated well with total bacterial numbers, but not with L. pneumophila numbers. At 53 °C, PEX pipes leached organic carbon, reducing the importance of dosed organic carbon. L. pneumophila numbers correlated with a Legionella OTU and a Methylophilus OTU identified by amplicon sequencing.ConclusionsTemperature was the most effective factor for the control of L. pneumophila, while microbiota composition shifted with each stepwise temperature increase. While copper pipe may also help shape the microbiota composition and limit L. pneumophila proliferation, its benefits might be constrained at higher temperatures. Influent assimilable organic carbon affected total bacterial numbers, but had minimal influence on opportunistic pathogen gene numbers or microbiota composition. These findings provide guidance among multiple control measures for the growth of opportunistic pathogens in hot water plumbing and insight into the mediating role of microbial ecological factors.

Interactive effects of temperature and genotype on almond ( Prunus dulcis L.) pollen germination and tube length

Abstract Some imperative developed genotypes of almond (‘Tardy Nonpareil’, ‘Nonpareil’, ‘Sahand’, ‘Rabie’, ‘Azar’, ‘Shekofeh’, ‘Sefied’ and ‘Mamaei’) were utilized in two experiments for 3 years to elucidate the genotype response of almond pollen germination and tube development at various temperature levels. Pollen was subjected to pre-incubation at 10, 20, 30 or 40∘C for 24 h to reproduce temperature stress during pollen dispersal; and then in vitro cultured. In the second examination, pollen was exposed at 15, 20, 25 or 30 °C for 24 h in vitro to assess pollen reaction in state of water and supplements accessibility and to determine the ideal pollen germination and tube development temperatures for every genotype. The most elevated pre- incubation temperature treatment (40 °C) completely prevented pollen germination in “Mamaei” and ‘Sefied’, while even in the less influenced cultivars ('Shekofeh’, ‘Azar’, ‘Rabie’, ‘Sahand’, ‘Tardy Nonpareil’ and ‘Nonpareil’) germination rates were as low as 2–3%. Pre-incubation at 30 ∘C or 40 °C negatively affected pollen germination and pollen tube length. In the second experiment, in vitro pollen germination increased after incubation at 25 °C for ‘Mamaei’ (+2%), ‘Sefied’ (+3%), ‘Shekofeh’ (+3%), ‘Azar’ (+3%), ‘Rabie’ (+4%), ‘Sahand’ (+5%), ‘Nonpareil’ (+5%) and ‘Tardy Nonpareil’ (+5%) compared to the control (20∘C). At 30 ∘C, germination percent for ‘Mamaei’, ‘Sefied’, ‘Shekofeh’, ‘Azar’, ‘Rabie’, ‘Sahand’, ‘Nonpareil’ and ‘Tardy Nonpareil’ was 35, 35, 10, 15, 25, 15, 35, and 20% lower, respectively, compared to the control (20 ∘C). Pollen tube length additionally increased with incubation temperature for all of the considered genotypes. In view of the cumulative stress response index (CSRI) that was calculated for high temperature stress the developed genotypes were arranged: ‘Shekofeh’ and ‘Tardy Nonpareil’ as tolerant and ‘Nonpareil’, ‘Rabie’ and ‘Sahand’ as intermediate at 40 ∘C, while ‘Azar’, ‘Rabie’, Sahand’ and ‘Tardy Nonpareil’ as tolerant, ‘Shekofeh’ and ‘Nonpareil’ as intermediate and ‘Mamaei’ and ‘Sefied’ as sensitive at 30 °C. The observed strong genotype differentiated reaction in high and low temperature stress could be utilized by plant breeders towards producing new tolerant almond genotypes.

Do rising temperatures always increase forest productivity? Interacting effects of temperature, precipitation, cloudiness and soil texture on tree species growth and competition

Forest landscape models (FLM) are increasingly used to project the effects of climate change on forested landscapes, yet most use phenomenological approaches with untested assumptions about future forest dynamics. We used a FLM that relies on first principles to mechanistically simulate growth (LANDIS-II with PnET-Succession) to systematically explore how landscapes composed of tree species with various life history traits respond to individual climate and abiotic drivers. Moderate temperature rise (+3 °C) concurrent with rising CO2 concentration increased net photosynthesis of cohorts, but decreased biomass production because of increased maintenance respiration costs. However, an increase of 6 °C decreased both photosynthesis and biomass production, regardless of species optimal temperature. Increasing precipitation generally increased photosynthesis and biomass. Reduced cloudiness had a positive effect on photosynthesis and biomass, but much less than the other treatment factors. Our study informs expectations for the outcome of modeling studies that project forest futures under climate change.

Thermal modulation of anthropogenic estrogen exposure on a freshwater fish at two life stages

Human-mediated environmental change can induce changes in the expression of complex behaviors within individuals and alter the outcomes of interactions between individuals. Although the independent effects of numerous stressors on aquatic biota are well documented (e.g., exposure to environmental contaminants), fewer studies have examined how natural variation in the ambient environment modulates these effects. In this study, we exposed reproductively mature and larval fathead minnows (Pimephales promelas) to three environmentally relevant concentrations (14, 22, and 65ng/L) of a common environmental estrogen, estrone (E1), at four water temperatures (15, 18, 21, and 24°C) reflecting natural spring and summer variation. We then conducted a series of behavioral experiments to assess the independent and interactive effects of temperature and estrogen exposure on intra- and interspecific interactions in three contexts with important fitness consequences; reproduction, foraging, and predator evasion. Our data demonstrated significant independent effects of temperature and/or estrogen exposure on the physiology, survival, and behavior of larval and adult fish. We also found evidence suggesting that thermal regime can modulate the effects of exposure on larval survival and predator-prey interactions, even within a relatively narrow range of seasonally fluctuating temperatures. These findings improve our understanding of the outcomes of interactions between anthropogenic stressors and natural abiotic environmental factors, and suggest that such interactions can have ecological and evolutionary implications for freshwater populations and communities.

Short-term and diurnal temperature changes alter the response of harmful algal blooms of Pseudo-nitzschia pungens to solar ultraviolet radiation

ABSTRACTIn this study, we explored the interactive effects of temperature and solar ultraviolet radiation (UVR) on the growth, pigment contents, photochemical efficiency and non-photochemical quenching (NPQ) of Pseudo-nitzschia pungens, which forms harmful algal blooms globally. Cells were first pre-acclimated to temperatures of 20°C, 25°C or 28°C for 10 days. They were then exposed to three different types of solar radiation for 60 min. We then measured the photochemical efficiency of the cells during the 60-min exposure and a 360-min recovery period under dim light (20 μmol photons m−2 s−1). In addition, we analysed the diural change in photochemical efficiency and NPQ over a 10-h period. We found that P. pungens that were exposed to higher temperatures in the short term (i.e. 20–25°C, 20–28°C and 25–28°C) or long term (i.e. 25–25°C and 28–28°C) exhibited lower levels of photoinhibition and faster recovery rates than samples exposed to a lower temperature (i.e. 20–20°C). This indicated that the deleterious effects of UVR can be minimised by both chronic and acute exposure to higher temperatures within the tolerated temperature range for P. pungens.

Interactive effects of temperature, food and skeletal mineralogy mediate biological responses to ocean acidification in a widely distributed bryozoan.

Marine invertebrates with skeletons made of high-magnesium calcite may be especially susceptible to ocean acidification (OA) due to the elevated solubility of this form of calcium carbonate. However, skeletal composition can vary plastically within some species, and it is largely unknown how concurrent changes in multiple oceanographic parameters will interact to affect skeletal mineralogy, growth and vulnerability to future OA. We explored these interactive effects by culturing genetic clones of the bryozoan Jellyella tuberculata (formerly Membranipora tuberculata) under factorial combinations of dissolved carbon dioxide (CO2), temperature and food concentrations. High CO2 and cold temperature induced degeneration of zooids in colonies. However, colonies still maintained high growth efficiencies under these adverse conditions, indicating a compensatory trade-off whereby colonies degenerate more zooids under stress, redirecting energy to the growth and maintenance of new zooids. Low-food concentration and elevated temperatures also had interactive effects on skeletal mineralogy, resulting in skeletal calcite with higher concentrations of magnesium, which readily dissolved under high CO2 For taxa that weakly regulate skeletal magnesium concentration, skeletal dissolution may be a more widespread phenomenon than is currently documented and is a growing concern as oceans continue to warm and acidify.

Is the chemical composition of biomass the agent by which ocean acidification influences on zooplankton ecology?

Climate change impacts prevail on marine pelagic systems and food webs, including zooplankton, the key link between primary producers and fish. Several metabolic, physiological, and ecological responses of zooplankton species and communities to global stressors have recently been tested, with an emerging field in assessing effects of combined climate-related factors. Yet, integrative studies are needed to understand how ocean acidification interacts with global warming, mediating zooplankton body chemistry and ecology. Here, we tested the combined effects of global warming and ocean acidification, predicted for the year 2100, on a community of calanoid copepods, a ubiquitously important mesozooplankton compartment. Warming combined with tested pCO2 increase affected metabolism, altered stable isotope composition and fatty acid contents, and reduced zooplankton fitness, leading to lower copepodite abundances and decreased body sizes, and ultimately reduced survival. These interactive effects of temperature and acidification indicate that metabolism-driven chemical responses may be the underlying correlates of ecological effects observed in zooplankton communities, and highlight the importance of testing combined stressors with a regression approach when identifying possible effects on higher trophic levels.

The interactive effects of temperature, trophic status, and the presence of an exotic clam on the performance of a native freshwater mussel

Global environmental changes constitute major threats to biodiversity in all ecosystems worldwide. Here we experimentally examined how temperature and trophic condition can influence the interaction between a highly invasive species and a native naiad species. We exposed the native freshwater mussel Unio delphinus to the presence/absence of the invasive Corbicula fluminea under three temperature levels and three trophic conditions. We used linear mixed models and hierarchical partitioning to model and test the independent effects of each variable in explaining U. delphinus feces production, which was used as a proxy for nutrient enrichment. Unio delphinus responded to high temperatures with higher clearance and respiration rates, showing an increase in energy expenditure. Feces production varied significantly with each factor and there was an interactive effect between the factors; increasing with temperature and trophic condition, and declining in the presence of the invasive clam. The hierarchical partitioning model showed that the system trophic condition and C. fluminea were the most important factors explaining feces production and to a lesser extent water temperature. Depletion of energetic reserves to cope with increasing temperatures could compromise the tolerance to additional stressors such as competition with invasive species or food reduction.

Interacting effects of temperature, habitat and phenotype on predator avoidance behaviour in Diadema antillarum: implications for restorative conservation

Caribbean long-spined sea urchin Diadema antillarum populations crashed following a mass mortality event in 1983-1984 with cascading effects on reef health. Population restoration efforts may be hampered by unknown effects of short- and long-term elevated sea surface temperature (SST). We investigated how a key behavioural trait, predator avoidance behaviour (PAB; percentage of long defensive spines that moved in response to shadow stimuli), was affected by elevated SST in 180 individuals from 2 contrasting Honduran reefs: Utila (flattened reef structure, dearth of predation refugia) and Banco Capiro (complex reef structure, abundant refugia). Initiation of PAB is mediated by melanin, which breaks down at elevated water temperatures; thus, as SST rises, D. antillarum may become vulnerable to predation. We compared local current SST (CSST; 29.7°C) with 2 IPCC predicted long-term climate change scenarios under laboratory conditions. PAB decreased by 13.98-15.37% at CSST +1.4°C and 31.67-42.44% at CSST +3.1°C. Trial temperatures were similar to maxima recorded in the Caribbean during the 2016 El Nino, so our results also represent likely responses to worst-case short-term acute temperature anomalies. Juveniles maintained higher PAB than adults, indicating increased reliance on anti-predation behaviours. White-spined phenotypes from Utila’s flattened reef maintained higher PAB than black-spined counterparts, likely due to increased conspicuousness to visual predators. Habitat complexity may mitigate temperature-driven losses in natural behavioural defences. D. antillarum may be resilient to near-term (<2039) SST increases and periodic temperature stresses but may struggle under long-term, worst-case scenario conditions. Restoration of D. antillarum populations must be coupled to augmented reef complexity to improve future resilience.

A Key Marine Diazotroph in a Changing Ocean: The Interacting Effects of Temperature, CO2 and Light on the Growth of Trichodesmium erythraeum IMS101.

Trichodesmium is a globally important marine diazotroph that accounts for approximately 60 − 80% of marine biological N2 fixation and as such plays a key role in marine N and C cycles. We undertook a comprehensive assessment of how the growth rate of Trichodesmium erythraeum IMS101 was directly affected by the combined interactions of temperature, pCO2 and light intensity. Our key findings were: low pCO2 affected the lower temperature tolerance limit (Tmin) but had no effect on the optimum temperature (Topt) at which growth was maximal or the maximum temperature tolerance limit (Tmax); low pCO2 had a greater effect on the thermal niche width than low-light; the effect of pCO2 on growth rate was more pronounced at suboptimal temperatures than at supraoptimal temperatures; temperature and light had a stronger effect on the photosynthetic efficiency (Fv/Fm) than did CO2; and at Topt, the maximum growth rate increased with increasing CO2, but the initial slope of the growth-irradiance curve was not affected by CO2. In the context of environmental change, our results suggest that the (i) nutrient replete growth rate of Trichodesmium IMS101 would have been severely limited by low pCO2 at the last glacial maximum (LGM), (ii) future increases in pCO2 will increase growth rates in areas where temperature ranges between Tmin to Topt, but will have negligible effect at temperatures between Topt and Tmax, (iii) areal increase of warm surface waters (> 18°C) has allowed the geographic range to increase significantly from the LGM to present and that the range will continue to expand to higher latitudes with continued warming, but (iv) continued global warming may exclude Trichodesmium spp. from some tropical regions by 2100 where temperature exceeds Topt.

Interactive effects of temperature and dietary supplementation of arginine or guanidinoacetic acid on nutritional and physiological responses in male broiler chickens

ABSTRACT1. The aim of this experiment was to study the interactive effect of rearing temperature and dietary supplementation of arginine (Arg) or guanidinoacetic acid (GAA) on performance, gut morphology and ascites indices in broiler chickens raised under the same condition in the first 2 weeks and then reared under normal (23–26°C) or subnormal (17°C) ambient temperatures for the next 3 weeks.2. This experiment was conducted as a split plot with 900 Ross 308 male broiler chicks that were allocated to two houses (as main plots); each consisted of 5 treatments (as sub-plots) with 6 replicates of 15 birds. The 5 diets were (1) control, (2) control + 0.60 g/kg GAA, (3) control + 1.20 g/kg GAA, (4) control + 0.86 g/kg Arg and (5) control + 1.72 g/kg Arg.3. Feed intake (0–35 d) of birds fed on a diet containing 1.2 g GAA/kg and reared under normal temperature was reduced compared to control fed birds. Birds fed on a diet containing 1.72 g/kg Arg and reared under subnormal temperature had higher weight gain compared to those fed on control or GAA-added diets in overall study period.4. Supplementation of diets with Arg alleviated the adverse effect of cold stress as reflected by reduction in blood haematocrit (41% vs. 37%), and right ventricle to total ventricle ratio (0.28 vs. 0.25) at 35 d of age. Addition of Arg to the diet of birds reared under cold stress resulted in a higher jejunal villus surface area compared to those fed on control or GAA-added diets.5. Findings of this study revealed that Arg or GAA supplementation of diets did not affect performance of birds under normal temperatures, but Arg supplementation of the diet significantly alleviated the adverse effect of cold stress on performance, gut development and ascites syndrome. In addition, GAA supplementation at 1.2 g/kg improved jejunal villus surface area in birds raised under subnormal temperature.

Individual and interactive effects of temperature, carbon dioxide and abscisic acid on mung bean (Vigna radiata) plants

ABSTRACTWe studied the effects of temperature, carbon dioxide and abscisic acid on mung bean (Vigna radiata). Plants were grown under 26/22°C or 32/28°C (16 h light/8 h dark) at 400 or 700 μmol mol−1 CO2 and received ABA application of 0 or 100 μl (10 μg) every other day for three weeks, after eight days of initial growth, in growth chambers. We measured 24 parameters. As individual factors, in 16 cases temperature; in 8 cases CO2; in 9 cases ABA; and as interactive factors, in 4 cases, each of temperature × CO2, and CO2 × ABA; and in 2 cases, temperature × ABA were significant. Higher temperatures increased growth, aboveground biomass, growth indices, photochemical quenching (qP) and nitrogen balance index (NBI). Elevated CO2 increased growth and aboveground biomass. ABA decreased growth, belowground biomass, qP and flavonoids; increased shoot/root mass ratio, chlorophyll and NBI; and had little role in regulating temperature–CO2 effects.Abbreviations: AN: net CO2 assimilation; E: transpiration; Fv/Fm: maximum quantum yield of PSII; gs: stomatal conductance; LAR: leaf area ratio; LMA: leaf mass per area; LMR: leaf mass ratio;φPSII: effective quantum yield of PSII; qNP: non-photochemical quenching; qP: photochemical quenching; SRMR: shoot to root mass ratio; WUE: water use efficiency

Interactive effects of ocean warming and acidification on sperm motility and fertilization in the mussel Mytilus galloprovincialis

MEPS Marine Ecology Progress Series Contact the journal Facebook Twitter RSS Mailing List Subscribe to our mailing list via Mailchimp HomeLatest VolumeAbout the JournalEditorsTheme Sections MEPS 562:101-111 (2016) - DOI: https://doi.org/10.3354/meps11944 Interactive effects of ocean warming and acidification on sperm motility and fertilization in the mussel Mytilus galloprovincialis Angela R. Eads*, W. Jason Kennington, Jonathan P. Evans Centre for Evolutionary Biology, University of Western Australia, Crawley, WA 6009, Australia *Corresponding author: angela.eads@graduate.uwa.edu.au ABSTRACT: Gametes of marine broadcast spawners are highly susceptible to the threats of ocean warming and acidification. Here, we explore the main and interacting effects of temperature and pH changes on sperm motility and fertilization rates in the mussel Mytilus galloprovincialis. Additionally, we determine how temperature and pH interact to influence the motility of aging sperm. We show that the interactive effects of temperature (18°C or 24°C) and pH (ranging from 7.6 to 8.0) on sperm motility depend on the time that sperm spend in these conditions. Specifically, sperm linearity was influenced by a temperature × pH interaction when measured after a relatively short exposure to the treatment conditions, while main effects of temperature and pH (but no interaction) on sperm motility became apparent only after prolonged exposure (2 h) to the treatments. Despite the interactive effects of temperature and pH on sperm motility, these factors had independent effects on fertilization rates, which were significantly higher at the ambient ocean pH level and at the elevated temperature. This study highlights the importance of considering the combined effects of predicted ocean changes on sperm motility and fertilization rates, and cautions against using only sperm motility as a proxy for reproductive fitness. Detrimental effects of pH and temperature may only be uncovered when these factors are examined together, or conversely, negative impacts of one variable may be buffered by changes in another. Our results raise the intriguing possibility that some species may cope better with ocean acidification if they simultaneously experience ocean warming. KEY WORDS: Ocean acidification · Ocean warming · Sperm motility · Fertilization · Broadcast spawner Full text in pdf format Supplementary material PreviousNextCite this article as: Eads AR, Kennington WJ, Evans JP (2016) Interactive effects of ocean warming and acidification on sperm motility and fertilization in the mussel Mytilus galloprovincialis. Mar Ecol Prog Ser 562:101-111. https://doi.org/10.3354/meps11944 Export citation RSS - Facebook - Tweet - linkedIn Cited by Published in MEPS Vol. 562. Online publication date: December 29, 2016 Print ISSN: 0171-8630; Online ISSN: 1616-1599 Copyright © 2016 Inter-Research.